Norway salmon prices seen rising to 77-78 crowns next week

* The average price of Norwegian farmed salmon is expected to rise next week, industry source told Reuters on Friday

* One producer, who declined to be named, expected an average price of around 77-78 crowns per kilo for deliveries in Oslo next week, up from around 74-75 crowns this week

* One exporter, also he unnamed, expected a rise of around two crowns to 77 crowns per kilo

* The exporter said current price level is not sustainable but less salmon available after Christmas holiday are driving prices upward

* The exporter said December sales from Norway was around 20 percent lower in 2016 compared to 2015

* Salmon prices have been volatile this year, hitting a record of 80 crowns per kilo in July, but then dropping to just above 50 crowns before rebounding towards the year's end

* Production costs in Norway have risen sharply in recent years to around 30-31 crowns per kilo on average

* Norway is the world's top salmon exporter, with leading producers including Marine Harvest, Salmar, Leroy Seafood, Grieg Seafood and Norway Royal Salmon

* Companies and analysts have predicted that the global supply of salmon will fall by 6-7 percent in 2016 due to declining production in Norway as well as in Chile, the world's second largest producer. ($1 = 8.6211 Norwegian crowns) (Reporting by Ole Petter Skonnord)